Elevator system



Sept. 18,1934. WILSON 1,973,920

ELEVATOR SYSTEM Filed March 25, 1931 2 Sheets-Sheet l avwemtoz lf atentecl Sept. 18, 1934 UNITED STATES:

FATE

1,973,920 [ELEVATOR SYSTEM Jacob D. Wilson, Brooklyn, N. Y. Application March 25, 1931, Serial No. 525,116 Claims. (01. 187-16) This invention relates to elevators, and aims to provide certain improvements therein.

In the construction of tall buildings, especially of the business building type, a considerable 6 amount of potential floor area has been utilized in the elevator shafts or wells. A greater appreciation of this fact has recently arisen, due to the building laws in a number of cities which require successive setbacks of the building as it progresses upward in height, which result in successively decreased floor space. toward the upper floors of the building. In some instances this is so marked that the upper floors are substantially towers, comprising a multiplicity of floors of small area which have been so cut down because of the necessary elevator shafts that not only is the floor area lost, but the remaining area has been reduced below that which is readily rentable. It is also true that per square foot of floor area such tower structures are expensive to build as compared with structures of larger cross-section. i

It has heretofore been'proposed to promote a saving in the elevator shafting by running two cars in a single shaft, one of such cars being local in its service and the other affording express service, a more or less complicated electric interlock being provided between the two cars, so as to avoid collision. Such service is satisfactory so long as the safety devices thus introduced work accurately, but they have the disadvantage of a double cable system, one for each car, a double driving system at the top of the shaft, and also a fear on the part of the public that on' occasions the interlocking safety system will not function. It has also been proposed to reinstate the old double-deck elevator car having two floors, but this necessarily places the entire weight of the car (which'approximates that of two single cars) and their occupants on the lifting cables running from the top of the double-decked car.

The present invention proposes a simple system of avoiding some of the disadvantages of both of these systems, and one which has advantages of its own.

To this end the invention comprises adouble elevator car system preferably running in a single shaft, the drive preferably comprising lifting cables running from the top of the upper 'car, and the lower car being connected to the upper car through a pulley system, one end of which is connected to the top of the elevator shaft so that the stationary beams located at the latter. point bear a portion of the weight of. the lower car. Preferably this system is so arranged. that the cables lead from the bottom of the upper car to the top of the lower car, and thence to the top of the shaft in such manner that the speed of the upper car is precisely twice that of the lower car. The invention has other features of novelty which will be hereinafter more fully described.

Referring to the drawings which illustrate several forms of the invention,-

Figure 1 is a diagrammatic drawing of a succession of floors of a building, showing the operation of my two-car system.

Fig. 2 is a similar view, showing a somewhat different ratio of drive.

Fig. 3 is a wiring diagram of a suitable control system.

Fig, 4 is a diagrammatic view of an extension of the invention,

Fig. 5 is a similar view of a modification.

Referring to Fig. 1, let A indicate any suitable building having an elevator well or shaft 13 extending from the bottom of the building to the top, the usual pent-house being omitted. The floors may be any desired number, although, of course, the invention is of greater utility in tall buildings than in low buildings. In Fig. l of the drawings I have illustrated seven lower floors with an indefinite extension at the top. These are numbered consecutively from 1 to '7.

C is the lower car and D the upper. The drive illustrated is'a cable E connected to the top of car D operated by a motor F having the usual counter-weight G. The lower car C is driven through a cable connection H leading from the bottom of the car D around appropriate sheaves I and J, and thence to the top where it is fastened to the usual supporting beam K at L. To secure a better'balance of the lower elevator, this is duplicated on the opposite side of the car, as shown at H, I, J andL.

The result of this arrangement is that when the upper car moves inthe shaft, the lower car is constrained to follow, but at one-half the speed of the upper car. It will be observed, therefore, that when the upper car D occupies a position at the second floor, the lower car is opposite the first floor. Arrangements are made in the building so that these twofloors constitute the lower terminals and are loaded for ascent on floors 2 and '1 respectively. ,Each of the cars may be provided withan operating control M or N which are shown as electric reversing switches, the two switches being connected in series or otherwise with the motor F to permit the stoppageof both cars by manipulating the switch handle of either, car. The invention is applicable to any of the modern methods of push button or other automatic types of signal control. In Fig. 3 I have shown a simple diagram of electrical connections for this purpose, from which it will be seen that the upper car switch and lower car switch are arranged in series with the usual hatchway door interlocks, and with the emergency switches for both cars and gate contacts for each car. Any approved automatic controller may be used, which controller is indicated diagrammatically in the drawings.

It will be observed that in the constructions just described the compensating cables for the upper car are utilized as the hoisting cables of the lower car. In case it is desired to compensate the lower car, a simple cable or chain attached at one end to the bottom of such car and at the other end to a fixed point in the shaft may be used, or a multiplying sheave may be-;placed on the bottom of the counterweight to provide the same ratio of speed reduction as that by which the car is raised.

The :method of installation and operation is by preference as follows, on the assumption that the system is designed to serve a forty-story building: The lower car is designed for local service, let us say up to the 20th floor, and the upper, car is designed for what may be called express service from the 20th to the 40th fioor. The two cars being opposite their respective loading floors, namely, floors 1 and 2 of the building, start upward; in the installation of Fig. 1 the upper car will travel two floors while the :lower car is travelling one door. If the lower car be assumed to stop at every floor from the first to the twentieth, the upper car will stop at every second floor. These stops of the upper car will :be idle until the lower car has reached the 10th floor, at which time the express car will have reached its first Stopping point, namely, the 20th floor. At that time if the express car stops at each floor from the 20th up, the lower car will make :idle stops between floors up to the 20th floor, at which time the express car has reached the top of the shaft and is opposite the 40th floor. Normally speaking then in practical operation, the two cars will be operated by the local operator alone until the local car reaches the 10th floor, and the express car the 20th floor, after whichboth cars will be operated by either operator as may be required by the service. 7

In most installations it willbe preferable to have the system duplicated a number of times in the bank of elevators, and instead of having the express elevators stop at all floors from the 20th to the 40th for example, one group of one-half of the express elevators will be designed'to stop at alternate odd floors and the other group at alternate even floors. This will eliminate stoppage of the local cars between floors.

It is, of course, not essential that the rat-i0 of travel of two to one be observed as any desired ratio can be utilized, such, for instance, as that shown in Fig. 2, wherein the lifting cable for the local car instead of being fastened at the bottom of the express car is fastened to the top of the local car at P and passes over a sheave Q at the bottom of the express car, and thence back to the two sheaves I and J. This will give a three to one ratio of movement which will result in the express car moving a distance of three floors while the local car is moving one floor. other ratio can'easily be obtained by suitable arrangement of sheaves.

In Fig. 4 of the drawings I have shown an extension of the invention in the provision of a secondary motor R at the top or other suitable point in the shaft, which motor replaces the dead-end connection L in Fig. 1 for the hoisting cable of the lower car. This motor is preferably provided with a brake S, by means of which the motor can be fixed against rotation. The provision of such a motor or other driving means is useful as a levelling device, so that the two cars may be separated a distance which corresponds accurately to that between two successive floors of the building and such multiples of this distance as oorrespond to the normal stopping points of the cars in practical operation. Another important advantage is that if by reason of accident or design it is desired to'suspend the operation of the upper car while still using the lower car, the upperc'armayb'e run to the top of the shaft and anchored such position, after which the lower car may continue in practical use by the operation of the secondary motor B. So also if a counterweight or its equivalent T is provided for the lower car, as shown in Fig. 4, so as to take up the slack of the driving cable of the lower car while the motor R. rotates idly, the upper car may be utilized while the lower car is anchored, let us say, at the bottom of the shaft. By these means a very considerable flexibility of the system can be obtained, since stoppage of one or the other car is permitted without interfering with the continued-cooperation of the car whichis left.

In Fig. 5 I have shown an application of the invention wherein the two cars are not mounted in the same shaft. In the construction illustrated in this figure the shafts are adjoining, and the fast car U is driven by the same motor as the slow car V. In the construction illustrated there is an arrangement of sheaves W and X, around which the cable Y is led, so that the fast car U operates at three times the speed of t e slow car V, and in this instance two-thirds "of the weight of the slow car is borne from a fixed point in the elevator shaft. As before, a single motor Z is adapted to run both cars. This arrangement is useful in mine shafts or the like where it may be a There are no interlocks required between the two cars. Unless there is a breakage of cable, it is impossible for the two cars to collide. Both cars operate with perfect safety, and this is secured irrespective of the acts of the operator. There will, of course, usually be employed the conventional safety systems which prevent cars from moving when at a landing with the shaft door open. Such safety systems require practically no change, since if it be assumed that both cars are at fioors delivering or taking on passengers, and one 'car has finished the operation before the other, and the shaft door is closed while the other one is open,. the usual safety interlock will opera-to, since in most cases such interlocks prevent the movement of the motor drive when any shaft door is open. Consequently, the delayed car in the instance given will prevent the opera.- tion of the driving motor until both shaft doors are closed. The effect of the combined operation of the two cars provided by this invention will be to enable the tenants of upper floors to reach their destinations much more quickly than they would by means of a local car running the entire height of the building, and, of course, the passenger load carried on the two cars will be approximately twice that which could be carried by a single loaded car. In many instances both cars will be serving their respective floors at the same time, and this is particularly true during rush hours. At other times both cars will doubtless pass a number of floors without stopping, so that additional speed will be gained.

By arrangement of Fig. 4, the additional advantages of independent operation and levelling may be attained.

While I have shown and described several forms of the invention, it will be understood that I do not wish to be limited thereto, since various changes may be made therein without departing from the spirit of the invention. For instance, if it be desired that the express car shall travel at a speed ratio with regard to the local car of three or more to one, and at the same time reduce the amount of weight to be carried, an arrangement similar to that shown in Fig. 5 may be adopted. With reference to Fig. 1, I have described a conventional arrangement wherein the lower car serves the first twenty floors of a building, and the upper car the twentieth to fortieth floors. It is evident, however, that this is a matter of choice, since in many installations it will be desired to run both cars as express cars, in which case for instance, the lower car will stop at no floor lower than, let us say, the tenth fioor, and serve from the tenth to the twentieth floors, making stops at all floors. instance can conveniently serve the twentieth to the fortieth floors also making stops at each of these floors if desired. Or the stops of the upper car can be staggered so that one car will serve only alternate fioors. In the instances just given a separate local service from the first to the tenth floors will be provided by other equipment.

What I claim is:

1. An elevator system, comprising two cars moving in the same shaft, a single means for driving both cars simultaneously, and means for driving either car independently of the other.

2. An elevator system comprising two cars arranged one above the other in the same shaft, means for driving the upper car, and means for driving the lower car at a reduced speed by the upper car and for sustaining only part of the weight of the lower car by the upper car.

3. An elevator system comprising an upper and a lower car arranged in the same shaft, means for driving the upper car, a sheave carried by the lower car, a cable connected with the upper car and passing around said sheave, and. a connection for such cable at a point beyond the range of travel of the lower car.

The upper car in this 4. An elevator system comprising an upper and a lower car operating in the same shaft, a motor for driving the upper car, a sheave on the lower car, and a cable passing from a fixed point with relation to the upper car around said sheave to a fixed point in the elevator shaft.

5. An elevator system comprising an upper and a lower car operating in the same shaft, a motor for driving the upper car, a sheave on the lower car, a cable passing from a fixed point with relation to the upper car around said sheave to a fixed point in the elevator shaft, and a similar sheave and cable on the opposite side of the lower car whereby the lower car is balanced.

6. An elevator system comprising an upper and a lower car travelling in the same shaft at different speeds, a single motor for driving both cars at such different rates of speed, speed reducing means operating to reduce the speed of the lower car as compared with that of the upper car in fixed ratio, and a control for each car, either control being adapted to stop cars, comprising electric switches controlling the driving motor, neither switch being operable alone to start the cars.

'7. An elevator system comprising two cars, a single motor for driving both cars simultaneously at different rates of speed in fixed ratio, driving means connecting said motor with said cars, the driving means for the slower car comprising a sheave and cable system operative to support a part of the weight of the slower car from a fixed point in the elevator shaft, and said driving means supporting another part of the weight from the motor.

8. An elevator system comprising two cars moving in the same direction in the same shaft, a single motor for driving both cars simultaneously at a fixed speed ratio, the faster car moving a greater distance than the slower car, and a secondary motor adapted to drive the slower car independently or the first motor.

9. An elevator system comprising two carsmoving in the same direction in the same shaft, a single motor for driving both cars simultaneously at a fixed speed ratio, the faster car moving a greater distance than the slower car, and means for moving at least one of said cars in dependently of said driving motor to adjust the relationship between the two cars.

10. An elevator system comprising twocars moving in the same direction in the same shaft, a single motor for driving both cars simultaneously at a fixed speed ratio, the faster car moving a greater distance than the slower car, a secondary motor adapted to drive the slower car independently or" the first motor, a cable through which said secondary motor drives the slower car, and a counterweight at the loose end of said cable. j l

JACOB D. WILSON. 

